Kesida It is also accessible to a broad range of engineering and science students, as well as valuable to practicing engineers seeking an insightful review. University of South Australia Library. Stuller has produced a text which is very readable, and would be excellent for self-study. Be the first to add this introduvtion a list.
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Samples of the signal are taken and preserved Examples Human voice , Thermometer , Analog phones e. The input is known as excitation and the output is known as response. In the above figure a system has been shown whose input and output both are signals but the input is an analog signal.
And the output is an digital signal. It means our system is actually a conversion system that converts analog signals to digital signals. Lets have a look at the inside of this black box system Conversion of analog to digital signals Since there are lot of concepts related to this analog to digital conversion and vice-versa. We will only discuss those which are related to digital image processing. There are two main concepts that are involved in the coversion.
Sampling Quantization Sampling Sampling as its name suggests can be defined as take samples. Take samples of a digital signal over x axis. Sampling is done on an independent variable. In case of this mathematical equation: Sampling is done on the x variable. We can also say that the conversion of x axis infinite values to digital is done under sampling.
Sampling is further divide into up sampling and down sampling. If the range of values on x-axis are less then we will increase the sample of values. This is known as up sampling and its vice versa is known as down sampling Quantization Quantization as its name suggest can be defined as dividing into quanta partitions.
Quantization is done on dependent variable. It is opposite to sampling. It is done on the y axis. The conversion of y axis infinite values to 1 , 0 , -1 or any other level is known as Quantization. These are the two basics steps that are involved while converting an analog signal to a digital signal. The quantization of a signal has been shown in the figure below.
Why do we need to convert an analog signal to digital signal. The first and obvious reason is that digital image processing deals with digital images , that are digital signals. So when ever the image is captured , it is converted into digital format and then it is processed.
The second and important reason is , that in order to perform operations on an analog signal with a digital computer , you have to store that analog signal in the computer. And in order to store an analog signal , infinite memory is required to store it.
And since thats not possible , so thats why we convert that signal into digital format and then store it in digital computer and then performs operations on it.
Continuous systems vs discrete systems Continuous systems The type of systems whose input and output both are continuous signals or analog signals are called continuous systems. Discrete systems The type of systems whose input and output both are discrete signals or digital signals are called digital systems.
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